by Carl Strang
(Note: This is a cross posting from the Observe Your Preserve website, a reference for all the forest preserves in DuPage County, their ecosystems and organisms, natural and cultural history).
The Forest Preserve District currently is engaged in a 350-acre wetland and prairie restoration project at West Branch Forest Preserve. Section by section, a mile-long stretch of the West Branch of the DuPage River is being diverted into a temporary channel while the main reach of the stream is improved: the unhealthy vertical banks receive a gentler profile, root logs are jammed into the outside bends to stabilize them, and riffles and pools are created to diversify the habitat and maximize the number of species that can live there.
October 4 was devoted to a search and rescue mission. The first reach of the stream was complete, and a dam blocked the next section, the bypass ushering the water over a plastic lining that prevented erosion and soil loss. With the water drained from the corresponding part of river channel, fishes and mussels had become stranded in shallow pools, and these needed rescuing before that part of the river improvement could proceed.
Forest Preserve District natural resources staff, along with volunteers and county staff, waded in and transferred the mussels, bucketsful of them. Four native species, identified with such colorful names as white heelsplitter, fatmucket, plain pocketbook and giant floater, got a ride into their new digs upstream.
A richer past was revealed by the empty shells of additional species whose larval hosts had gone locally extinct (newly hatched mussels attach to the gills of fishes and live a temporary parasitic life). Stream improvement projects like this offer hope of a return to this past diversity. As for the fishes, a backpack electric shocker facilitated the netting of more than 10 kinds of them. The bass and crappies, shiners and chubs, bullheads, suckers, and sunfish temporarily resided in buckets with oxygen bubblers before being carried back to the main flowage.
The stream channel improvement is scheduled to be completed this year, with a large acreage of associated new wetlands and prairies on either side due to be built in 2014.